Gigabit Ethernet – A Short Overview

Introduction of Ethernet

Ethernet was introduced as an industry standard for computer networking in 1970s. Since then, ethernet has seen immense advancement in speed and reliability. It is estimated that until mid 1990s, majority of the networking equipment was based on the ethernet standard. Ethernet provided 10 Mbps of throughput. Soon this speed became obsolete and demand for higher throughput started rising. IEEE formed an alliance called the Fast Ethernet Alliance to upgrade the ethernet standard to 100 Mbps. 100 Mbps ethernet was a major step forward providing ten times higher bandwidth than its predecessor. Fast ethernet is still being used in some of the smaller networks especially homes and very small branch offices.

Introduction of Gigabit Ethernet

The ever-growing need for higher bandwidths and throughputs urged the scientists and engineers to devise new methods to meet this demand. In late 1990s, IEEE formed another alliance called the Gigabit Ethernet Alliance to standardize 1000 Mbps ethernet technology. Gigabit ethernet was standardized in 1998 as IEEE 802.3z standard. Since then, gigabit ethernet has become the de-facto standard of almost every computer network in the world. The popularity of gigabit ethernet is still on the rise despite 10 Gbps and 40 Gbps ethernet standards being readily available.

Let us discuss the gigabit ethernet in some detail to better understand its basics. Gigabit ethernet is a data link layer technology, the primary purpose of gigabit ethernet is to provide the connectivity interface to physical layer medium such as UTP cables and fiber optic cables. Theoretically, gigabit ethernet supports 1000 Mbps of throughput over category 5 UTP cable and the variant 1000BASE-X supports the same throughput over fiber optic cables.

Most of the networking equipment today, supports gigabit ethernet. Even if the end-used equipment such as laptop or personal computer doesn’t support gigabit ethernet, the gigabit ethernet switch can still be used to connect it to the network as it is backwards compatible with ethernet and fast ethernet technologies. Almost all of the original equipment manufacturers offer auto-sensing ports that can adjust the speed of the port to match that of the end-user equipment.

Variants of Gigabit Ethernet

There are several variants of the gigabit ethernet technology that are used with different type of physical media. Table 1 shows a list of gigabit ethernet variants and their associated cable types. It also gives an indication of the maximum link length possible with each type of the cable.

Table 1: Gigabit Ethernet Variants

Future of Gigabit Ethernet

Gigabit ethernet is widely being used all over the world, the popularity and usage of gigabit ethernet is not showing any signs of fading away, largely because the more advanced technologies such as 10 Gbps ethernet, 40 Gbps ethernet and 100 Gbps ethernet are very costly and do not seem feasible even for the larger enterprises. Gigabit ethernet will remain the first choice networking technology unless the higher bandwidth ethernet becomes more cost effective.